About the Percentage Calculator
Percentages turn up in almost every business decision: a supplier offers 7% off, sales grow from ₹8 lakh to ₹9.2 lakh, a commission is 2.5% of the invoice, a loan processing fee is 1% of the amount. This calculator answers the three questions people actually ask, without making you remember which number goes on top of the fraction.
The first mode finds a percentage of a number, such as 18% of 25,000, and also shows the number with that percentage added and removed — handy for GST, commissions and discounts. The second tells you what share one number is of another, for example what percent 450 is of 1,800. The third measures the percentage increase or decrease from an old value to a new one.
Results appear as you type and are rounded to two decimal places. Percentage change is always measured against the old value, which is why a rise from 80 to 100 is 25% but a fall from 100 to 80 is only 20%. If the old value is zero the change has no meaning, so the tool says so instead of showing an error.
How to use it
- 1Pick the question you want answered: X% of Y, X is what % of Y, or % change from X to Y.
- 2Enter the two numbers. Decimals and negative values are accepted.
- 3Read the main result in the dark box; the two boxes beside it show related figures, such as the number plus and minus the percentage.
- 4Switch modes at any time — each mode remembers the numbers you typed.
How this is calculated
X% of Y = Y × X ÷ 100 X as a percentage of Y = X ÷ Y × 100 Percentage change from X to Y = (Y − X) ÷ |X| × 100 — a positive answer is an increase, a negative one a decrease.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For 18% of 25,000, that is 25,000 × 18 ÷ 100 = 4,500. To add the percentage, as with GST, add the result to the original number to get 29,500; to take it off, as with a discount, subtract it to get 20,500.
How do I work out a percentage increase or decrease?
Subtract the old value from the new value, divide by the old value and multiply by 100. Sales rising from 80,000 to 92,000 give (92,000 − 80,000) ÷ 80,000 × 100 = 15% growth. If the answer is negative, the value has fallen by that percentage.
Why is a 20% fall not cancelled out by a 20% rise?
Because each percentage is measured on a different base. A price of 100 that falls 20% becomes 80; a 20% rise on 80 adds only 16, taking it to 96. To get back to 100 from 80 you need a 25% increase. The same logic applies to losses and recoveries in any investment.
What is the difference between percent and percentage points?
Percentage points measure the simple gap between two percentages, while percent measures relative change. If an interest rate moves from 10% to 12%, it has risen by 2 percentage points, but by 20 percent in relative terms. Mixing the two is a common source of confusion when comparing loan offers or margins.
Can I use this for marks, GST and commission?
Yes. For marks, use the second mode: marks obtained as a percentage of total marks. For GST or commission, use the first mode to find the percentage of the invoice value and read the number plus the percentage for the tax-inclusive total. For year-on-year growth, use the percentage change mode.